System and method for an aftercooler bypass

Abstract

Embodiments of systems and methods for bypassing an aftercooler are disclosed. According to one embodiment, the bypass valve system may include a turbocharger, an air temperature sensor, an aftercooler, a three-way bypass valve, an aftercooler conduit, a bypass conduit, a pipe fitting, an engine, a radiator, an expansion tank, a pump, a bypass control system and a locomotive control system. The temperature of the charge air is measured and sent to the bypass control system. The locomotive control system sends engine throttle conditions, such as engine notch position, to bypass control system. Bypass control system determines whether to circulate coolant through the aftercooler or bypass the aftercooler based on the temperature measurements and the engine throttle conditions. Bypass control system then sends a signal to the bypass valve to either to circulate coolant through the aftercooler or bypass the aftercooler through the conduit.

What is claimed is: 
     
       1. A cooling system for an internal combustion engine comprising:
 a turbocharger; and 
 a single coolant loop comprising:
 a radiator, 
 an engine coolant expansion tank, 
 an aftercooler for receiving combustion air from the turbocharger, the aftercooler comprising an air-to-liquid heat exchanger for exchanging heat between the combustion air and a liquid coolant, 
 an engine, 
 a liquid coolant pump for continuously circulating liquid coolant throughout the single coolant loop, 
 a liquid coolant bypass conduit that bypasses the aftercooler, 
 a temperature sensor for measuring an ambient air temperature, and 
 a three-way bypass valve for controlling a flow of the liquid coolant to the aftercooler and the liquid coolant bypass conduit, the three-way bypass valve comprising:
 an inlet for receiving the liquid coolant from the expansion tank, 
 an outlet for supplying the liquid coolant to the aftercooler, and 
 an outlet for supplying the liquid coolant to the liquid coolant bypass conduit, 
 
 
 wherein the three-way bypass valve diverts the liquid coolant to the aftercooler or diverts the liquid coolant to the liquid coolant bypass conduit based on a throttle position of the internal combustion engine and the measured ambient air temperature, and wherein the three-way bypass valve diverts the liquid coolant to the liquid coolant bypass conduit when the ambient air temperature is lower than a liquid coolant temperature. 
 
     
     
       2. The cooling system of  claim 1 , wherein the three-way bypass valve diverts the liquid coolant to the liquid coolant bypass conduit when the ambient air temperature is lower than a specified temperature. 
     
     
       3. The cooling system of  claim 1 , wherein the three-way bypass valve diverts the liquid coolant to the liquid coolant bypass conduit when the ambient air temperature is lower than a specified temperature and the throttle position of the internal combustion engine is within a specified range. 
     
     
       4. The cooling system of  claim 1 , further comprising a bypass control system that controls the three-way bypass valve, the bypass control system configured to receive information associated with the throttle position of the internal combustion engine and the ambient air temperature. 
     
     
       5. The cooling system of  claim 1 , wherein the liquid coolant is a heat transfer fluid selected from a group consisting of water, engine oil, and fuel. 
     
     
       6. The cooling system of  claim 1 , wherein the three-way bypass valve diverts all of the liquid coolant to the aftercooler or diverts all of the liquid coolant to the liquid coolant bypass conduit based on the throttle position of the internal combustion engine and the ambient air temperature. 
     
     
       7. The cooling system of  claim 6 , wherein the aftercooler is cooled by ambient air when the three-way bypass valve diverts all of the liquid coolant to the liquid coolant bypass conduit. 
     
     
       8. The cooling system of  claim 1 , wherein the throttle position of the internal combustion engine has an idle position and eight discrete notch positions, and wherein a load increase request is issued by moving the throttle position from a first notch position to a higher notch position. 
     
     
       9. The cooling system of  claim 8 , wherein the three-way bypass valve diverts the liquid coolant to the aftercooler when the ambient air temperature is below 70.degree. F. 
     
     
       10. The cooling system of  claim 8 , wherein the three-way bypass valve diverts the liquid coolant to the liquid coolant bypass conduit when the ambient air temperature is above 70.degree. F. and the throttle position of the internal combustion engine is in one of discrete notch positions idle, and one through four. 
     
     
       11. The cooling system of  claim 1 , wherein the three-way bypass valve is a pneumatic valve further comprising an air supply port and air exhaust port. 
     
     
       12. The cooling system of  claim 11 , further comprising:
 an air supply; 
 a conduit for passing air from the air supply to the air supply port of the three-way bypass valve; and 
 a magnet valve for controlling air flow to the three-way bypass valve. 
 
     
     
       13. The cooling system of  claim 12 , wherein a bypass control system controls the diversion of the liquid coolant in the three-way bypass valve by controlling the magnet valve. 
     
     
       14. The cooling system of  claim 1 , further comprising a pipe fitting for receiving the liquid coolant from the aftercooler and the three-way valve. 
     
     
       15. The cooling system of  claim 14 , wherein the pipe fitting is a welded tee. 
     
     
       16. The cooling system of  claim 15 , further comprising a bypass pipe connecting the aftercooler to the outlet for supplying the liquid coolant to the aftercooler. 
     
     
       17. The cooling system of  claim 16 , wherein the pipe fitting is 1.25 inches in diameter, and the bypass pipe is 1 inch in diameter. 
     
     
       18. A method for cooling an internal combustion engine having a turbocharger and a coolant loop, the method comprising the steps of:
 measuring an ambient air temperature by a temperature sensor; 
 measuring a temperature of a liquid coolant that is continuously circulated in a single coolant loop, the single coolant loop comprising a radiator, an engine coolant expansion tank, and an aftercooler having an air-to-liquid heat exchanger for exchanging heat between a combustion air from an engine and the liquid coolant; 
 determining a throttle position of the internal combustion engine, wherein a load increase request is issued by moving the throttle position from a first notch position to a higher notch position; and 
 employing a three-way bypass valve to either circulate the liquid coolant to the aftercooler or circulate the liquid coolant to a liquid coolant bypass conduit that bypasses the aftercooler based on the ambient air temperature and the throttle position, wherein the three-way bypass valve diverts the liquid coolant to the liquid coolant bypass conduit when the ambient air temperature is lower than a temperature of the liquid coolant. 
 
     
     
       19. The method of  claim 18 , wherein the three-way bypass valve diverts the liquid coolant to the liquid coolant bypass conduit when the ambient air temperature is lower than a specified temperature. 
     
     
       20. The method of  claim 18 , further comprising the step of controlling the three-way bypass valve to divert all of the liquid coolant to the aftercooler or divert all of the liquid coolant to the liquid coolant bypass conduit based on a throttle position of the internal combustion engine and the ambient air temperature. 
     
     
       21. The method of  claim 20 , wherein the aftercooler is cooled by ambient air when the three-way bypass valve diverts all of the liquid coolant to the liquid coolant bypass conduit. 
     
     
       22. The method of  claim 18 , wherein the three-way bypass valve diverts the liquid coolant to the liquid coolant bypass conduit when the ambient air temperature is lower than a specified temperature and the throttle position is within a specified range. 
     
     
       23. The method of  claim 11 , wherein the three-way bypass valve diverts the liquid coolant to the aftercooler when the ambient air temperature is below 70.degree. F. 
     
     
       24. The method of  claim 22 , wherein the three-way bypass valve diverts the liquid coolant to the liquid coolant bypass conduit when the ambient air temperature is above 70.degree. F. and the throttle position is in one of discrete notch positions one through four.